Tibial trial system for a knee prosthesis and method

ABSTRACT

An orthopaedic surgical instrument system for use during a surgical procedure to implant an orthopaedic knee prosthesis includes a tibial trial component adapted to be positioned on a surgically-prepared proximal end of a patient&#39;s tibia. The tibial trial component has a base plate and a central post extending upwardly from a superior surface of the base plate. A superior surface of the central post has a ramp surface defined therein, with the ramp surface inclining superiorly in the anterior-to-posterior direction.

This application is a continuation application and claims priority toU.S. patent application Ser. No. 16/390,667, now U.S. Pat. No.10,952,863, which is a continuation application that claims priorityunder 35 U.S.C. § 121 to U.S. patent application Ser. No. 15/866,047,now U.S. Pat. No. 10,265,183, which is a divisional application thatclaims priority under 35 U.S.C. § 121 to U.S. patent application Ser.No. 14/265,960, now U.S. Pat. No. 9,861,491, each of which is expresslyincorporated herein by reference.

CROSS-REFERENCE

Cross-reference is made to U.S. patent application Ser. No. 13/530,771,now U.S. Pat. No. 8,986,390, entitled “SYSTEM AND METHOD FOR TRIALING AKNEE PROSTHESIS” by Tom Wogoman et al. and filed on Jun. 22, 2012, U.S.patent application Ser. No. 13/530,662, now U.S. Pat. No. 8,951,301,entitled “METHOD OF USING A TRIALING SYSTEM FOR A KNEE PROSTHESIS” byTom Wogoman et al. and filed on Jun. 22, 2012, and U.S. patentapplication Ser. No. 13/530,649, now U.S. Pat. No. 8,968,412, entitled“TRIALING SYSTEM FOR A KNEE PROSTHESIS AND METHOD OF USE” by Tom Wogomanet al. and filed on Jun. 22, 2012, each of which is assigned to the sameassignee as the present application, and each of which is herebyincorporated by reference.

TECHNICAL FIELD

The present disclosure relates generally to orthopaedic surgicalinstruments and, more particularly, to surgical instruments used with apatient's tibia.

BACKGROUND

Joint arthroplasty is a well-known surgical procedure by which adiseased and/or damaged natural joint is replaced by a prosthetic joint.A typical knee prosthesis includes a patella prosthetic component, atibial tray, a femoral component, and a polymer insert or bearingpositioned between the tibial tray and the femoral component. Femoralcomponents are designed to be attached to a surgically-prepared distalend of a patient's femur. Tibial trays are designed to be attached to asurgically-prepared proximal end of a patient's tibia.

To facilitate the replacement of the natural joint with the kneeprosthesis, orthopaedic surgeons use a variety of orthopaedic surgicalinstruments such as, for example, prosthetic trial components, cuttingblocks, drill guides, milling guides, and other surgical instruments.Prosthetic trial components, such as, for example, a femoral trialcomponent and a tibial bearing trial component, are used to size andselect the components of the knee prosthesis that will replace thepatient's natural joint. A procedure that utilizes the trial componentsto size and select the components of the knee prosthesis is oftenreferred to as a trial reduction.

SUMMARY

According to one aspect of the disclosure, an orthopaedic surgicalinstrument system for use during a surgical procedure to implant anorthopaedic knee prosthesis includes a tibial base trial componentadapted to be positioned on a surgically-prepared proximal end of apatient's tibia. The tibial base trial component has an opening definedtherein. The instrument system also includes an insert component shapedto be received in the opening defined in the tibial base trialcomponent. The insert component has a base plate and a central postextending upwardly from a superior surface of the base plate. A superiorsurface of the central post has a ramp surface defined therein, with theramp surface inclining superiorly in the anterior-to-posteriordirection. The instrument system also includes a tibial bearing trialcomponent having an opening defined therein. The central post of theinsert component is configured to be received in the opening of thetibial bearing trial assembly.

The central post may include a collar extending outwardly from thelongitudinal axis of the central post, with the ramp surface beingdefined in a superior surface of the collar. Such a ramp surface definedin the collar may include an anterior end and a posterior end. Theanterior end of the ramp surface defined in the collar is coplanar withthe superior surface of the base plate, and the posterior end of theramp surface defined in the collar is spaced apart superiorly from thesuperior surface of the base plate.

The central post may include a connector configured to secure the insertcomponent to a surgical handle. The connector includes a flangeextending anteriorly away from the longitudinal axis of the centralpost, with the ramp surface being defined in a superior surface of theflange of the connector.

The central post may also include an elongated anti-rotation lugextending in a direction away from the longitudinal axis of the centralpost, with the ramp surface being defined in a superior surface of theelongated anti-rotation lug.

The insert component may be embodied as a tibial evaluation componenthaving a pair of bone engaging spikes extending inferiorly from theinferior surface thereof.

The tibial bearing trial component may include a tibial bearing surfacetrial component having an articular surface, and a shim removablysecured to the tibial bearing surface trial component.

The insert component may be embodied as a keel punch, with the keelpunch having a pair of serrated wings extending inferiorly from theinferior surface of the insert component.

According to another aspect, a surgical instrument for use to surgicallyprepare a proximal end of a patient's tibia during a surgical procedureto implant an orthopaedic knee prosthesis includes a keel punch. Thekeel punch includes a base plate, and a central post extending upwardlyfrom a superior surface of the base plate. A superior surface of thecentral post has a ramp surface defined therein, with the ramp surfaceinclining superiorly in the anterior-to-posterior direction. The keelpunch also includes pair of serrated wings extending inferiorly from aninferior surface of the base plate.

The central post may include a collar extending outwardly from thelongitudinal axis of the central post, with the ramp surface beingdefined in a superior surface of the collar. The anterior end of theramp surface defined in the collar is coplanar with the superior surfaceof the base plate, and the posterior end of the ramp surface defined inthe collar is spaced apart superiorly from the superior surface of thebase plate.

The central post may include a connector configured to secure the keelpunch to a surgical handle. The connector includes a flange extendinganteriorly away from the longitudinal axis of the central post, and theramp surface is defined in a superior surface of the flange of theconnector.

The central post may further include an elongated anti-rotation lugextending in a direction away from the longitudinal axis of the centralpost. The ramp surface is defined in a superior surface of the elongatedanti-rotation lug.

The surgical punch further may further include a tapered cylindricalpost extending inferiorly from the inferior surface of the base plate.One of the pair of serrated wings is secured to a medial side of thetapered cylindrical post and extends medially therefrom, with the otherserrated wing being secured to a lateral side of the tapered cylindricalpost and extending laterally therefrom.

According to another aspect, a method of trialing prosthetic componentsof a knee prosthesis includes positioning a tibial base trial componenton a surgically-prepared proximal end of a patient's tibia, andinserting an insert component into an opening defined in the tibial basetrial component. The insert component has a base plate and a centralpost extending upwardly from a superior surface of the base plate. Thesuperior surface of the central post has a ramp surface defined therein.The method also includes advancing a tibial bearing trial component inthe anterior-to-posterior direction such that a leading edge of thetibial bearing trial component contacts, and rides up, the ramp surfaceso as to urge a posterior edge of the tibial bearing trial componentsuperiorly in a direction away from the tibial base trial component.

A femoral trial component and the tibial base trial component are urgedin a direction away from one another during advancement of the tibialbearing trial component.

The tibial bearing trial component may a tibial bearing surface trialcomponent secured to a shim. A leading edge of the shim contacts, andrides up, the ramp surface so as to urge a posterior edge of the tibialbearing surface trial component superiorly in a direction away from thetibial base trial component during advancement of the tibial bearingtrial component.

The central post comprises a collar extending outwardly from thelongitudinal axis of the central post, with the ramp surface beingdefined in a superior surface of the collar. A leading edge of the shimcontacts, and rides up, the ramp surface of the collar so as to urge aposterior edge of the tibial bearing surface trial component superiorlyin a direction away from the tibial base trial component duringadvancement of the tibial bearing trial component.

The central post includes a connector configured to secure the insertcomponent to a surgical handle. The connector includes a flangeextending anteriorly away from the longitudinal axis of the centralpost, with the ramp surface being defined in a superior surface of theflange of the connector. A leading edge of the tibial bearing surfacetrial component contacts, and rides up, the ramp surface of theconnector so as to urge a posterior edge of the tibial bearing surfacetrial component superiorly in a direction away from the tibial basetrial component during advancement of the tibial bearing trialcomponent.

The central post also includes an elongated anti-rotation lug extendingin a direction away from the longitudinal axis of the central post, withthe ramp surface being defined in a superior surface of the elongatedanti-rotation lug. A leading edge of the shim contacts, and rides up,the ramp surface of the anti-rotation lug so as to urge a posterior edgeof the tibial bearing surface trial component superiorly in a directionaway from the tibial base trial component during advancement of thetibial bearing trial component.

The insert component may define a tibial evaluation component, with thetibial evaluation component having a pair of bone engaging spikesextending inferiorly from the inferior surface of the insert component.The bone engaging spikes of the tibial evaluation component are insertedthrough the opening defined in the tibial base trail component and intobone tissue.

The insert component may be embodied as a keel punch, with the keelpunch having a pair of serrated wings extending inferiorly from theinferior surface of the insert component. The serrated wings of the keelpunch are inserted through the opening defined in the tibial base trailcomponent and into bone tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIG. 1 is an exploded perspective view of an orthopaedic surgicalinstrument system;

FIG. 2 is a perspective view of the tibial evaluation component of theorthopaedic surgical instrument system of FIG. 1 ;

FIG. 3 is a side elevation view of the tibial evaluation component ofFIG. 2 ;

FIG. 4 is a cross sectional view of the tibial evaluation componenttaken along the line 4-4 of FIG. 2 , as viewed in the direction of thearrows;

FIG. 5 is a cross sectional view of the tibial evaluation componenttaken along the line 5-5 of FIG. 2 , as viewed in the direction of thearrows;

FIG. 6 is an exploded perspective view of the tibial base trialcomponent, the tibial evaluation component, and a number of tibialbearing trial components of the orthopaedic surgical instrument systemof FIG. 1 ;

FIG. 7 is an exploded perspective view of a keel punch used with thetibial base trial component of the orthopaedic surgical instrumentsystem of FIG. 1 ;

FIG. 8 is a perspective view of the keel punch of FIG. 7 ;

FIG. 9 is a side elevation view of the keel punch of FIG. 8 ;

FIG. 10 is a cross sectional view of the keel punch taken along the line10-10 of FIG. 8 , as viewed in the direction of the arrows;

FIG. 11 is a cross sectional view of the keel punch taken along the line11-11 of FIG. 8 , as viewed in the direction of the arrows;

FIGS. 12-15 are views of a patient's femur, tibia, and the orthopaedicsurgical instrument system of FIGS. 1-11 as the orthopaedic surgicalinstrument system is used in the performance of a surgical procedure toimplant a knee prosthesis;

FIG. 16 is a top elevation view showing the tibial bearing trialcomponent of the of the orthopaedic surgical instrument system beingadvanced onto either the tibial evaluation component or the keel punch;and

FIGS. 17-20 are cross sectional views taken along their respective linesof FIG. 16 (as viewed in the direction of the arrows) showing the tibialbearing trial component during various stages of anterior advancementonto either the tibial evaluation component or the keel punch.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

Terms representing anatomical references, such as anterior, posterior,medial, lateral, superior, inferior, etcetera, may be used throughoutthe specification in reference to the orthopaedic implants and surgicalinstruments described herein as well as in reference to the patient'snatural anatomy. Such terms have well-understood meanings in both thestudy of anatomy and the field of orthopedics. Use of such anatomicalreference terms in the written description and claims is intended to beconsistent with their well-understood meanings unless noted otherwise.

Referring to FIGS. 1-11 , an orthopaedic surgical instrument system 10(hereinafter system 10) is shown. The system 10 is used during jointarthroplasty procedures, such as a total knee replacement procedure. Itshould be appreciated, however, that although the system 10 is describedbelow in regard to the performance of a total knee replacementprocedure, certain concepts associated with the system 10 may beutilized in replacement procedures of numerous other joints throughoutthe body.

As shown in FIG. 1 , the system 10 has a number of trial components 12,including a tibial base trial component 14, a number of insertcomponents 16, a femoral trial component 18, and a number of tibialbearing trial components 20. The system 10 also includes a tibial keelpunch 22 (see FIG. 7 ) and a number of surgical tools, such as, forexample, an alignment handle 26 and an impaction handle 28 (see FIG. 12), which are used to manipulate the trial components 12 and the othersurgical instruments during the performance of an orthopaedic surgicalprocedure, as described in greater detail below.

The system 10 may be utilized to size and select the prostheticcomponents of a knee prosthesis that will replace the patient's naturaljoint. To do so, the femoral trial component 18 is attached to asurgically-prepared distal end 600 of a patient's femur 602 (see FIG. 13), whereas the tibial base trial component 14 is attached to asurgically-prepared proximal end 604 of a patient's tibia 606 (see FIG.13 ). One of the tibial bearing trial components 20 is positioned on thetibial base trial component 14 between the femoral trial component 18and the tibial base trial component 14. As described in greater detailbelow, the surgeon uses the system 10 in a trial reduction process todetermine the type and configuration of each of the various types ofprosthetic components that are to be implanted.

The system 10 may be also utilized to surgically prepare the proximalend 604 of a patient's tibia 606 for implantation of a tibial prostheticcomponent, such as a tibial tray, during the performance of anorthopaedic surgical procedure. The tibial base trial component 14 andthe guide tower 24 are positioned on the proximal end 604 of thepatient's tibia 606, and the surgeon uses the trial component 14 and thetower 24 to guide, for example, a surgical drill while reaming theproximal end 604 of the patient's tibia 606. Thereafter, the keel punch22 is impacted into the proximal end 604 of the patient's tibia 606before the guide tower 24 is removed. An additional trial reduction maybe performed with the keel punch 22 before the surgeon installs thecomponents of the knee prosthesis, as described in greater detail below.

As can be seen in FIG. 1 , the base trial component 14 includes a plate30 having an upper surface 32, a lower surface 34, and an outer sidewall36 extending between the surfaces 32, 34. The plate 30 has a plateopening 38 defined in the upper surface 32. The plate opening 38 has acentral opening 40 and a pair of elongated openings 42 extendingoutwardly therefrom. An inner wall 44 extends downwardly from theopening 38 to define a passageway 46 through the plate 30. The innerwall 44 includes an upper wall 48 and a lower wall 50 offset orotherwise spaced inwardly from the upper wall 48. The upper wall 48 andlower wall 50 cooperate to define a shelf surface 52 therebetween. Aswill be discussed in greater detail below, the configuration of thepassageway 46 permits the advancement of various surgical drills,punches, and other instruments into the proximal end 604 of thepatient's tibia 606. It should be appreciated that the tibial base trialcomponent 14 may be formed in a number of different sizes to accommodatetibias of various sizes.

The plate 30 also includes a lever-receiving notch 54 that is defined inan anterior aspect 56 thereof. The notch 54 is configured to receive alever 66 associated with the alignment handle 26 (see FIG. 15 ).

Referring now to FIGS. 2-5 , the insert component 16 is embodied as atibial evaluation component or “evaluation bullet”. The tibialevaluation components 16 are configured to be positioned separately inthe plate opening 38 of the base trial component 14. Each tibialevaluation component 16 has a base plate 78 having a peripheral rim 82defined therein. The rim 82 has an inferior surface 84 configured toengage the shelf surface 52 of the base trial component 14 when thetibial evaluation component 16 is seated on the base trial component 14.The base plate 78 includes a central platform 86 sized to be received inthe central opening 40 of the base trial component 14. The body 80 alsoincludes a pair of prongs 88, 90 that extend outwardly from the centralplatform 86. The prongs 88, 90 are sized to be received in the elongatedopenings 42 of the base trial component 14.

The base plate 78 of the tibial evaluation component 16 includes acentral post 94 extending upwardly from a superior surface 96 thereof.The post 94 has a connector 98 formed in its superior end. The connector98 is configured to receive a locking flange associated with theimpaction handle 28 so as to secure the tibial evaluation component 16to the handle 28. The connector 98 includes a flange 100 that extendsanteriorly away from the longitudinal axis of the central post 94. Theflange 100 has a ramp surface 102 defined therein. In particular, aninferior surface 104 of the flange 100 extends substantially parallel tothe superior surface 96 of the tibial evaluation component's base plate78, whereas the flange's superior surface 106 inclines superiorly in theanterior-to-posterior direction. In other words, as can be seen clearlyin FIG. 3 , the anterior edges of the flange's superior surface 106 andinferior surface 104 converge on one another to form a leading edge 108of the flange 100. The superior surface 106 inclines superiorly in theanterior-to-posterior direction such that the distance in which thesuperior surface 106 of the flange 100 is spaced apart from the inferiorsurface 104 is greater at the end of the flange 100 opposite its leadingedge 108. As will be discussed below in greater detail, such a rampsurface facilitates installation of the tibial bearing trial assembly20.

As shown best in FIGS. 2 and 4 , the central post 94 also has an opening112 defined in its superior end. An inner wall extends downwardly fromthe opening 112 to define a central passageway 114 through the tibialevaluation component 16. The opening 112 is configured to receive aguide pin (not shown) associated with the impaction handle 28 (see FIG.12 ). The inner wall of the central passageway 114 has a keyed section(not shown) that permits the tibial evaluation component 16 to beattached to the impaction handle 28 in only a single predeterminedorientation.

The central post 94 of the tibial evaluation component 16 has ananti-rotation block or lug 120 extending outwardly from the post'scurved sidewall toward the prong 90. As will be described in greaterdetail below, the anti-rotation lug 120 engages the tibial bearing trialcomponent 20 to prevent or permit the tibial bearing trial component 20from rotating relative to the tibial base trial component 14. It shouldbe appreciated that in other embodiments the lug 120 might be formed in,for example, the other side of the central post 94 so as to extendtoward the prong 88. It should also be appreciated that in otherembodiments the tibial evaluation component 16 may include additionalanti-rotation lugs. In the illustrative embodiment, the anti-rotationlug 120 has a ramp surface 116 defined therein. In particular, as can beseen in FIG. 2 , a portion of the lug's anterior superior surface 118inclines superiorly in the anterior-to-posterior direction. As will bediscussed below in greater detail, such a ramp surface 116 facilitatesinstallation of the tibial bearing trial assembly 20.

The central post 94 of the tibial evaluation component 16 has a pair ofcollars 122 extending outwardly from the longitudinal axis of the post94. As can be seen in FIG. 2 , one of the collars 122 extends outwardlytoward the prong 90, with the other collar extending toward the prong88. The superior surface of each of the collars 122 has a ramp surface124 defined therein. The collar's ramp surface 124 inclines superiorlyin the anterior-to-posterior direction. In particular, as can be seenbest in FIGS. 3 and 5 , an anterior end 126 of the ramp surface 124 iscoplanar with the superior surface 96 of the tibial evaluationcomponent's base plate 78, whereas the ramp surface's posterior end 128is spaced apart superiorly from the superior surface 96 of the tibialevaluation component's base plate 78. As a result, the ramp surface 124inclines superiorly in the anterior-to-posterior direction. As will bediscussed below in greater detail, such a ramp surface facilitatesinstallation of the tibial bearing trial assembly 20.

Returning to FIG. 1 , the tibial evaluation component 16 may be embodiedas a spiked component and a spikeless component. The spiked tibialevaluation component 16 includes a pair of mounting spikes 130 thatextend downwardly from the prongs 88, 90, respectively. Each spike 130includes an upper cylindrical section 134 and a pointed conical tip 136configured to engage the proximal end 604 of the patient's tibia 606,thereby temporarily securing the base insert 126 to the proximal end 604of the patient's tibia 606.

As discussed above, the system 10 also includes a femoral trialcomponent 18 that is configured to be secured to the distal end 600 ofthe patient's femur 602 (see FIG. 13 ). One example of a femoral trialis shown and described in co-pending U.S. patent application Ser. No.13/530,239, which published as U.S. Patent App. Pub. No. 2013/0006378and is entitled “POLYMER FEMORAL TRIAL COMPONENT” by Thomas Wogoman andfiled Jun. 22, 2012, which is expressly incorporated herein byreference. The femoral trial component 18 is configured to assist thesurgeon in selecting a femoral prosthetic component, which will emulatethe configuration of the patient's natural femoral condyles. As such,the femoral trial component 18 includes a pair of condyle surfaces 140,142, which may be shaped (i.e., curved) in a manner that approximatesthe condyles of the natural femur.

Referring now to FIG. 6 , a number of tibial bearing trial components 20of the system 10 are shown. As discussed above, in the illustrativeembodiment described herein, the tibial bearing trial components 20 area multi-piece assembly configured to assist the surgeon in selecting asize and configuration of a prosthetic tibial bearing component of theknee prosthesis. As shown in FIG. 6 , a given tibial bearing trialcomponent 20 may be assembled with one of a number of tibial bearingsurface trial components 192 and one of a number of a plurality of trialshims 190. In an embodiment, the bearing surface trial components 192may be provided in different sizes and/or configurations, and each shim190 may have a different thickness. Because each shim 190 is configuredto be secured to each bearing surface trial component 192, the surgeonis able to assemble a tibial bearing trial component 20 of one size andconfiguration, evaluate the performance of that tibial bearing trialcomponent 20, and then modify the tibial bearing trial component 20 asnecessary to determine intraoperatively the type and configuration ofthe prosthetic tibial bearing component to be implanted.

As can be seen in FIG. 6 , each of the tibial bearing trial components20 has a leading edge 194 defined in a posterior surface 196 thereof. Aswill be described in greater detail below, during installation of thetibial bearing trial component 20, the leading edge 194 of the tibialbearing trial component 20 contacts and rides up the ramp surfaces ofthe tibial evaluation component 16 so as to facilitate installation ofthe tibial bearing trial component 20 without subluxation of thepatient's tibia 606.

Returning to FIG. 6 , one of the bearing surface trial components 192 isa fixed bearing surface trial component. The term “fixed bearing surfacetrial component” as used herein refers to a bearing surface trial thatis fixed in position relative to the tibial base trial component 14 whenthe bearing surface trial component 192 and shim 190 are attachedthereto (i.e., it is configured to not substantially rotate or move inthe anterior-posterior direction or medial-lateral direction relative tothe tibial base trial component 14). Such a fixed bearing surface trialcomponent 192 may be embodied as a cruciate retaining trial, a posteriorstabilized trial, a revision trial, or other surface trialconfiguration, per the surgeon's preference.

The other bearing surface trial 192 shown in FIG. 6 is embodied as amobile bearing surface trial component. The term “mobile bearing surfacetrial component” as used herein refers to a bearing surface trialcomponent that is permitted to rotate relative to the tibial base trialcomponent 14 when the bearing surface trial and the shim are attachedthereto (i.e., it is configured to substantially rotate or move in theanterior-posterior direction or the medial-lateral direction relative tothe tibial base trial component 14). The mobile bearing surface trialcomponent may be embodied as a cruciate retaining trial, a posteriorstabilized trial, a revision trial, or other surface trialconfiguration, per the surgeon's preference. Liked the fixed version, inembodiments where the mobile bearing surface trial component is embodiedas a posterior stabilized trial, the mobile bearing surface trialcomponent may include a spine extending upwardly from the upper bearingsurface thereof.

The surgeon may assemble one of the shims 190 with one of the bearingsurface trial components 192 to form a tibial bearing trial component20. For example, the surgeon may select one of the fixed bearing surfacetrial components 192 and secure the shim 190 thereto to form a fixedbearing trial component 20. During a surgical trialing procedure, thefixed bearing trial component is advanced such that the anti-rotationlug 120 is received in a slot 232 of the shim 190 and the central post94 is received in a central passageway 222 of the shim. The inner wallsof the shim 190 cooperate with the anti-rotation lug 120 to prevent thefixed bearing trial component from rotating relative to the base trialcomponent 14.

Alternatively, the surgeon may assemble one of the shims 190 with one ofthe mobile bearing surface trial components 192 to form a mobile bearingtrial component 20. During a surgical trialing procedure, the mobilebearing trial component is advanced such that the anti-rotation lug 120is received in the slot 234 of the shim 190 and the central post 94 isreceived in the central passageway 222 of the shim. The size and arcuateshape of the slot 234 of the shim 190 permits the mobile bearing trialcomponent to rotate relative to the base trial component 14. When themobile bearing trial component is rotated in one direction, theanti-rotation lug 120 acts as a stop to permit rotation of a defineddistance such as, for example, approximately fifty degrees.

Referring now FIGS. 7-11 , the system 10 further includes a keel punch22. The keel punch 22 is configured to be inserted through the plateopening 38 of the base trial component 14 into the proximal end 604 ofthe patient's tibia 606 to prepare the patient's tibia 606 for aprosthetic component. The keel punch 22 has a base plate 78 having aperipheral rim 82 defined therein. The base plate 78 of the keel punch22 has a configuration similar to the base plate 78 of the tibialevaluation components 16. As such, like reference numerals are utilizedin the description of the keep punch 22 to describe features that aresimilar to those features already discussed in regard to the tibialevaluation components 16. The rim 82 of the keel punch's base plate 78has an inferior surface 84 configured to engage the shelf surface 52 ofthe base trial component 14 when the keel punch 22 is seated on the basetrial component 14. The base plate 78 of the keel punch 22 also includesa central platform 86 sized to be received in the central opening 40 ofthe base trial component 14, along with a pair of prongs 88, 90 thatextend outwardly from the central platform 86. The prongs 88, 90 aresized to be received in the elongated openings 42 of the base trialcomponent 14.

As can be seen in FIGS. 7-11 , the central post 94 of the keel punch 22is identical to the central post 94 of the tibial evaluation component16. As such, the flange 100 of the post's connector 98 has a rampsurface 102 defined therein, with a ramp surface 116 also being definedin the post's anti-rotation lug 120. Ramp surfaces 124 are also definedin each of the post's collars 122. In a similar manner to as describedabove in regard to the tibial evaluation component 16, such rampsurfaces facilitate installation of the tibial bearing trial component20 to the keel punch 22.

As can be seen in FIGS. 7 and 8 , a tapered cylindrical post or bullet138 extends inferiorly from the inferior surface of the keel punch'sbase plate 78. A pair of serrated wings 140 extend outwardly away fromthe bullet 138. One of the serrated wings 140 extends medially from themedial side of the bullet 138, with the other serrated wing extendinglaterally from the lateral side of the bullet 138. The bullet 138 hascircular cross section that varies in diameter along its length (i.e.,the diameter of the bullet 138 tapers in the superior-inferiordirection). In that way, the cross sectional diameter of the bullet 138at an upper end is greater than the cross sectional diameter of thebullet 138 at its lower end (i.e., its tip). A number of downwardlyextending teeth 142 are defined in each of the serrated wings 140. Theteeth 142 are configured to engage the patient's tibia 606 to define anopening in the proximal end 604 of the patient's tibia 606 sized toreceive a tibial implant.

As described above, the system 10 also includes the guide tower 24 (seeFIG. 14 ), which is configured to be positioned on the base trialcomponent 14 during use. One example of a guide tower is shown anddescribed in U.S. patent application Ser. No. 13/530,952, now U.S. Pat.No. 8,852,197, entitled “SURGICAL INSTRUMENT ASSEMBLIES FOR USE INSURGICALLY PREPARING A TIBIA FOR IMPLANTATION OF A PROSTHETIC COMPONENT”by David Waite et al., which is incorporated herein by reference. Theguide tower 24 is used by a surgeon to align and guide advancement ofthe keel punch 22 into the patient's tibia 606.

Referring now to FIGS. 12-15 , portions of an orthopaedic surgicalprocedure utilizing the system 10 is shown. The surgeon first performs aresection of the distal end 600 of the patient's femur 602 and aresection of the proximal end 604 of the patient's tibia 606 tosurgically prepare those ends for trial reduction. For example, thesurgically-prepared proximal end 604 of the patient's tibia 606 alsoincludes a resected surface 614 configured to receive the tibial basetrial component 14.

The surgeon then performs an initial trial reduction. In doing so, thesurgeon uses the system 10 to evaluate and check the stability andkinematics of the patient's femur 602 and tibia 606 for implantation ofa fixed bearing knee prosthesis or a mobile bearing knee prosthesis. Inthe trial reduction process, the surgeon installs the femoral trialcomponent 18 on the distal end 600 of the patient's femur 602, as shownin FIG. 13 .

As shown in FIG. 12 , the surgeon also positions the tibial base trialcomponent 14 on the resected surface 614 of the patient's tibia 606. Thesurgeon may then select one of the tibial evaluation components 16 to beplaced in the plate opening 38 of the base trial component 14. If thesurgeon desires a fixed bearing trial component, the surgeon may selecta spikeless tibial evaluation component 16 and position it in the plateopening 38 by hand so that the inferior surface 84 of the component'srim 82 engages the shelf surface 52 of the base trial component 14. Ifthe surgeon desires a mobile bearing trial component, the surgeon mayselect a spiked tibial evaluation component 16, as shown in FIG. 12 .

To position the spiked tibial evaluation component 16 in the plateopening 38 of the base trial component 14, the surgeon may attach thetibial evaluation component 16 to the impaction handle 28. The tibialevaluation component 16 and impaction handle 28 are then positioned overthe plate opening 38, and the surgeon may then apply force to the handle28 to tap the tibial evaluation component 16 into the proximal end 604of the patient's tibia 606. In doing so, the spikes 130 extending fromthe prongs 88, 90 of the tibial evaluation component 16 are driven intothe proximal end 604 of the patient's tibia 606. The surgeon continuesdriving the tibial evaluation component 16 into the patient's tibia 606until the inferior surface 84 of component's rim 82 engages the shelfsurface 52 of the tibial base trial component 14.

Once the selected tibial evaluation component 16 (i.e., spiked orspikeless) is properly seated, the surgeon may select a trial shim 190and a tibial bearing surface trial component 192. If the surgeon desiresa fixed bearing trial component, a fixed bearing surface trial component192 may be selected and attached to one of the trial shims 190.

The surgeon then advances the posterior edge of the assembled tibialbearing surface trial component 192 and shim 190 into the gap betweenthe tibial base trial component 14 and the femoral trial component 18.As can be seen in the progressive motion views of FIGS. 16-20 , as theposterior/leading edge 194 of the tibial bearing surface trial component192 and the posterior/leading edge 194 of the shim 190 are moved in theanterior-to-posterior direction, the leading edges 194 contact the rampsurfaces 102, 116, 124 of the tibial evaluation component's central post94 and ride up the ramp surfaces 102, 116, 124. As the leading edges ofthe tibial bearing surface trial component 192 and the shim 190 ride upthe ramp surfaces 102, 116, 124 of the tibial evaluation component'scentral post 94, the posterior edge of the tibial bearing surface trialcomponent 192 is urged superiorly in a direction away from the tibialbase trial component 14 thereby likewise urging the femoral trialcomponent 18 superiorly in a direction away from the tibial base trialcomponent 14 (see FIGS. 18 and 19 ). This increases the size of the gapbetween tibial base trial component 14 and the femoral trial component18 so as to allow the assembled tibial bearing surface trial component192 and shim 190 to be slipped therebetween with little to nosubluxation of the patient's tibia 606. As shown in FIG. 20 , once theleading edge of the slot 232 formed in the shim 190 clears the trailingedge of the anti-rotation lug 120, the shim 190 (and hence the tibialbearing surface trial component 192 secured thereto) snaps down into aposition in which the anti-rotation lug 120 is received in a slot 232 ofthe shim 190 and the central post 94 is received in a central passageway222 of the shim.

As shown in FIG. 13 , when the fixed bearing trial component 20 is inplace, the surgeon carefully extends the knee of the patient, noting theanteroposterior stability, medial-lateral stability, and overallalignment in the anterior-posterior (“A/P”) plane and medial-lateral(“M/L”) plane. Rotational alignment of the tibial base trial component14 may be adjusted with the knee in full extension, using the handle 26to rotate the trial 14 and the bearing trial component 20 relative tothe femoral trial component 18. The rotation of the base trial component14 is usually centered on the junction between the medial and centralone-third of the tibial tubercle.

As the range of motion is evaluated, the load on the femoral trialcomponent 18 translates posteriorly as the knee is moved betweenextension and flexion. To improve performance, the surgeon may removethe fixed bearing trial component 20 from the tibial base trialcomponent 14 to exchange the shim 190 and/or the bearing surface trialcomponent 192. A removal tool (not shown) may be used to detach thefixed bearing trial component 20 from the base trial component 14. Thesurgeon may use a separator tool (not shown) to detach the shim 190 fromthe fixed bearing surface trial component 192. The surgeon may thenselect another shim 190 having a different thickness or choose a fixedbearing surface trial component 192 with an alternative configuration,such as, for example, a fixed bearing surface trial component 192 thatis cruciate retaining or posterior stabilized. In some cases, thesurgeon may switch to a mobile bearing surface trial component 192. Thesurgeon may continue to try various combinations of shims 190 andbearing surface trial components 192 to ascertain which final implantwill have the best stability in flexion and extension while permittingfull extension. Once the revised combination of a shim 190 and bearingsurface trial component 192 is selected, the two components areassembled to one another and anteriorly advanced in the gap betweentibial base trial component 14 and the femoral trial component 18 in themanner previously discussed.

If the surgeon desires instead a mobile bearing trial component 20, amobile bearing surface trial component 192 may be selected and attachedto one of the trial shims 190. The surgeon then advances the posterioredge of the assembled tibial bearing surface trial component 192 andshim 190 into the gap between the base trial component 14 and thefemoral trial 18 in the same manner as described above in regard to thefixed bearing trial component 20. As can be seen in the progressivemotion views of FIGS. 16-20 , as the posterior/leading edge 194 of thetibial bearing surface trial component 192 and the posterior/leadingedge 194 of the shim 190 are moved in the anterior-to-posteriordirection, the leading edges contact the ramp surfaces 102, 116, 124 ofthe tibial evaluation component's central post 94 and ride up the rampsurfaces 102, 116, 124. As the leading edges of the tibial bearingsurface trial component 192 and the shim 190 ride up the ramp surfaces102, 116, 124 of the tibial evaluation component's central post 94, theposterior edge of the tibial bearing surface trial component 192 isurged superiorly in a direction away from the tibial base trialcomponent 14 thereby likewise urging the femoral trial component 18superiorly in a direction away from the tibial base trial component 14(see FIGS. 18 and 19 ). This increases the size of the gap betweentibial base trial component 14 and the femoral trial component 18 so asto allow the assembled tibial bearing surface trial component 192 andshim 190 to be slipped therebetween with little to no subluxation of thepatient's tibia 606. Once the leading edge of the arcuate slot 234formed in the shim 190 clears the trailing edge of the anti-rotation lug120, the shim 190 (and hence the tibial bearing surface trial component192 secured thereto) snaps down into a position in which theanti-rotation lug 120 is received in the slot 234 of the shim 190 andthe central post 94 is received in a central passageway 222 of the shim.As described above, the size and arcuate shape of the slot 234 of theshim 190 permits the mobile bearing trial component 20 to rotaterelative to the base trial component 14. When the mobile bearing trialcomponent 20 is rotated in one direction, the anti-rotation lug 120 actsas a stop to permit rotation of a defined distance such as, for example,approximately fifty degrees.

With the femoral trial component 18, the tibial base trial component 14,and the mobile bearing trial component 20 in place, the surgeon mayextend the knee and note the anteroposterior stability, medial-lateralstability, and overall alignment in the A/P and M/L planes. The surgeonis also able to assess the bearing rotation and patellofemoral trackingbecause the mobile bearing trial component 20 is rotatable about thebase trial component 14.

Once the surgeon is satisfied with the trial reduction, the tibial trialcomponent 20 and the tibial evaluation component 16 are removed from thetibial base trial component 14.

Referring now to FIG. 14 , after performance of the trial reduction, thesurgeon then continues surgical preparation of the proximal end 604 ofthe patient's tibia 606. Specifically, the guide tower 24 is positionedon tibial base trial component 14 so that its fixation pins (not shown)extend through the designated holes of the tibial base trial component14 and into the proximal end 604 of the patient's tibia 606. The surgeonmay then use the base trial component 14 and the tower 24 as a guide tosurgically ream the proximal end 604 of the patient's tibia 606.Thereafter, as shown in FIG. 14 , the keel punch 22 is impacted into theproximal end 604 of the patient's tibia 606 using the impaction handle28 before the guide tower 24 is removed. An exemplary procedure forreaming the patient's tibia 606 and installing the keel punch 22 is setforth in U.S. patent application Ser. No. 13/530,945, now U.S. Pat. No.8,926,619, entitled “METHOD OF SURGICALLY PREPARING A TIBIA FORIMPLANTATION OF A PROSTHETIC COMPONENT” filed by David Waite et al. andfiled on Jun. 22, 2012, which is incorporated herein by reference.

Subsequently, the surgeon determines whether any additional trialreduction is necessary. If so, the surgeon may utilize the keel punch 22seated on the tibial base trial component 14 in the proximal end 604 ofthe patient's tibia 606 to perform an additional trial reduction. Asshown in FIG. 15 , the surgeon may assemble a fixed bearing trialcomponent 20 or a mobile bearing trial component 20 and anteriorlyadvance the trial component 20 into the gap between tibial base trialcomponent 14 and the femoral trial component 18 and over the centralpost 94 and the anti-rotation lug 120 of the keel punch 22 in the samemanner as described above in regard to the tibial evaluation component16 with little to no subluxation of the patient's tibia 606. The surgeonmay then repeat the trial reduction until satisfied with the alignmentand the stability of the knee.

When the additional trial reduction is complete, the surgeon may use theimpaction handle 28 to remove the keel punch 22 from the patient's tibia606. The resultant features surgically formed in the proximal end 604 ofthe patient's tibia 606 are configured to receive a tibial tray of afixed bearing knee prosthesis or a mobile bearing knee prosthesis. Thesurgeon then completes the surgical procedure of the remainingcomponents of the prosthesis.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such an illustration and descriptionis to be considered as exemplary and not restrictive in character, itbeing understood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the method, apparatus, and system describedherein. It will be noted that alternative embodiments of the method,apparatus, and system of the present disclosure may not include all ofthe features described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations of the method, apparatus, andsystem that incorporate one or more of the features of the presentinvention and fall within the spirit and scope of the present disclosureas defined by the appended claims.

The invention claimed is:
 1. An orthopaedic surgical instrument systemfor use during a surgical procedure to implant an orthopaedic kneeprosthesis, comprising: a tibial trial component configured to bepositioned on a surgically-prepared proximal end of a patient's tibia,the tibial trial component having a base plate and a central postextending upwardly from a superior surface of the base plate, wherein asuperior surface of the central post has a ramp surface defined therein,the ramp surface inclines superiorly in an anterior-to-posteriordirection.
 2. The orthopaedic surgical system of claim 1, wherein: thecentral post comprises a collar extending outwardly from a longitudinalaxis of the central post, and a ramp surface is defined in a superiorsurface of the collar.
 3. The orthopaedic surgical system of claim 2,wherein: the ramp surface defined in the collar has an anterior end anda posterior end, the anterior end of the ramp surface defined in thecollar is coplanar with the superior surface of the base plate, and theposterior end of the ramp surface defined in the collar is spaced apartsuperiorly from the superior surface of the base plate.
 4. Theorthopaedic surgical system of claim 1, wherein: the central postcomprises a connector configured to be secured to a surgical handle, theconnector comprising a flange extending anteriorly away from alongitudinal axis of the central post, and the ramp surface defined inthe central post is defined in a superior surface of the flange of theconnector.
 5. The orthopaedic surgical system of claim 1, wherein: thecentral post further comprises an elongated anti-rotation lug extendingin a direction away from a longitudinal axis of the central post, andthe ramp surface defined in the central post is defined in a superiorsurface of the elongated anti-rotation lug.
 6. An orthopaedic surgicalinstrument system for use during a surgical procedure to implant anorthopaedic knee prosthesis, comprising: a tibial trial componentconfigured to be positioned on a surgically-prepared proximal end of apatient's tibia, the tibial trial component having a base plate and acentral post extending upwardly from a superior surface of the baseplate, wherein a superior surface of the central post has a ramp surfacedefined therein, the ramp surface inclines superiorly in ananterior-to-posterior direction, and a bearing trial component having anopening defined therein, the central post of the tibial trial componentbeing configured to be received in the opening of the bearing trialcomponent.
 7. The orthopaedic surgical system of claim 6, wherein: thecentral post comprises a collar extending outwardly from a longitudinalaxis of the central post, and a ramp surface is defined in a superiorsurface of the collar.
 8. The orthopaedic surgical system of claim 7,wherein: the ramp surface defined in the collar has an anterior end anda posterior end, the anterior end of the ramp surface defined in thecollar is coplanar with the superior surface of the base plate, and theposterior end of the ramp surface defined in the collar is spaced apartsuperiorly from the superior surface of the base plate.
 9. Theorthopaedic surgical system of claim 6, wherein the bearing trialcomponent comprises: a tibial bearing surface trial component having anarticular surface, and a shim removably secured to the tibial bearingsurface trial component.
 10. The orthopaedic surgical system of claim 6,wherein: the central post comprises a connector configured to be securedto a surgical handle, the connector comprising a flange extendinganteriorly away from a longitudinal axis of the central post, and theramp surface defined in the central post is defined in a superiorsurface of the flange of the connector.
 11. The orthopaedic surgicalsystem of claim 6, wherein: the central post further comprises anelongated anti-rotation lug extending in a direction away from alongitudinal axis of the central post, and the ramp surface defined inthe central post is defined in a superior surface of the elongatedanti-rotation lug.